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VLC Video Conversion - exceptionally slow?

Posted: 27 Apr 2019 16:58
by timg11
I'm running VLC 3.0.6 on Windows 10, i7 4GHz system.

I'm converting a 50 minute video from MP4 to OGG.
After 20 minutes of elapsed time, VLC has converted 55 seconds of video.

Checking the CPU, VLC is using about 12% -- partially using one of 8 cores. The system is otherwise idle.

Are there any settings that can enable VLC to use more system resources to run faster?

Re: VLC Video Conversion - exceptionally slow?

Posted: 27 Apr 2019 21:22
by Ed Edison
Hi,

No problem here with your configuration.

Same codecs
(3.0.6) vlc.exe --no-repeat --no-loop -I rc -vv --no-lua "G:\xxx.mp4" --stop-time=120.0 --sout=file/avformat{mux=matroska}:"G:\xxx.ogg" (wrong duration)
(3.0.6) vlc.exe --no-repeat --no-loop -I rc -vv --no-lua "G:\xxx.mp4" --stop-time=120.0 --sout=file/ps:"G:\xxx.ogg"

Different codecs
(3.0.6) vlc.exe --no-repeat --no-loop -I rc -vv --no-lua "G:\Essai\xxx.mp4" --stop-time=120.0 --swscale-mode=1 :sout=#transcode{vcodec=theo,scale=Auto,acodec=vorb,ab=256,channels=2,samplerate=44100,scodec=none}:file{mux=ogg,dst="G:\xxx.ogg"}

See https://wiki.videolan.org/Ogg/ and the Log file produced.

Re: VLC Video Conversion - exceptionally slow?

Posted: 29 Apr 2019 15:06
by unidan
Hi, in preferences, advances, input/Codec -> video codecs -> ffmpeg, what is the value of "threads" ? Can you post the logs to show which encoder is used ?

To help you, we need messages, to completely understand what your problems is.
To fix this, please be sure before you start the playback to:
  1. Open: Tools -> Messages.
  2. Set Verbosity to 2
  3. Start playback to reproduce your issue
  4. Save text in a file or copy into clipboard
  5. Then paste the full resulting log here between [​code]and[​/code] (or use Pastebin.com if it's too long)
Also don't forget to name your Operating System and provide the VLC media player version.

Re: VLC Video Conversion - exceptionally slow?

Posted: 27 Nov 2022 13:52
by ApeGana
Hi everybody,
back to this old thread because I have approximately the same problem.
I'm trying to use VLC to convert video files in H264 in order to compress them. It works, but it is very slow since it only uses 6% of the cpu.
My CPU has got 8 cores and 16 theads: I guess that VLC uses only one thread, given that 100/16=6.
Is there a way to force VLC to use more CPU?

Operative system: Windows 10 Pro vers. 22H2
CPU: AMD Ryzen 7 2700X
Ram: 16GB

As suggested by Unidan, here below the debug log during the conversion:
https://pastebin.com/hu2PYdSn

Many thanks to who will try to help me.